New technique welcomes calcium-41 to radiometric dating

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Last Updated23/05/2023

A recent study has shown that Calcium-41 can be used in a similar way as Carbon-14 in carbon dating, but with several advantages.

Carbon-14 is an unstable and weakly radioactive isotope of carbon.
It has a half-life of 5,700 years and is used to estimate the age of carbon-based materials.
Radiocarbon dating provides objective age estimates for materials from living organisms.
Carbon-14 cannot determine the age of objects older than approximately 50,000 years.
Three techniques are used to measure carbon-14 content: gas proportional counting, liquid scintillation counting, and accelerator mass spectrometry.

Calcium-41 is a rare long-lived radioisotope of calcium with a half-life of 99,400 years.
It is produced through cosmic ray interactions in the soil and is found in the Earth’s crust.
Calcium-41 occurs less frequently than carbon-14.

ATTA is a technique proposed by researchers at the University of Science and Technology of China.
It is based on laser manipulation and detection of neutral atoms.
The sample is vaporized, and the atoms are laser-cooled and loaded into a light and magnetic field cage.
By tuning the laser’s frequency, Calcium-41 atoms can be detected through electron transitions.

ATTA can detect one Calcium-41 atom in every 10^16 calcium atoms in seawater with 12% precision.
It is selective and avoids confusion with potassium-41 atoms.
ATTA can be adapted to study other isotopes, such as argon-39, krypton-81, and krypton-85.
The applications of ATTA and Calcium-41 include dating rocks covered by ice and exploring Earth-science applications.